Virus-derived sequences in the nuclear genome of grapevine
Résumé
Bioinformatic analyses of two nuclear genomes of grapevine revealed multiple events of horizontal gene transfer from pararetroviruses. The ~200-800 bp inserts apparently derived from unknown or extinct caulimo- and tungroviruses were found in 11 chromosomes. These inserts corresponded to partial ORFs encoding reverse transcriptase. Because there are no known grapevine pararetroviruses, this result suggests that viral inserts have conferred host resistance to these viruses. In addition, a ~50 bp insert originating from Grapevine leafroll-associated virus-1, a positive-strand RNA closterovirus, was present in chromosome 1. This insert was also found in the genomes of several North American and Asian Vitaceae species.